Endoluminal grafting is a relatively noninvasive method for placing a tubular graft within the lumen of an anatomical conduit, such as a blood vessel. In certain cardiovascular applications of the technique, an endovascular graft may be implanted within an aneurysmic segment of a blood vessel (i.e., a blood vessel which has a region of localized dilatation wherein the blood vessel wall has become distended and weakened) to form a prosthetic flow conduit through the aneurysm, and to effectively isolate weakened portion of the blood vessel wall from the hemodynamic forces and pressures of the flowing blood.
The prior art has included numerous endovascular grafts of varying design. In general, these endovascular grafts typically comprise: a tube of pliable material (e.g., expanded polytetrafluoroethylene (ePTFE) or woven polyester) in combination with a graft anchoring component (e.g., a stent, a frame, a series of wire rings, hooks, barbs, clips, staples, etc.) which operates to hold the tubular graft in its intended position within the blood vessel. Most commonly, the graft anchoring component is formed of a radially expandable stent or frame which is either a) incorporated into the body of the tubular graft or b) formed separately from the graft and deployed within the graft lumen, and which is expandable to exert outwardly directed radial pressure against the surrounding blood vessel wall--thereby frictionally holding the graft in place. In operation, endovascular grafts which incorporate radially expandable graft anchoring devices are initially disposed in a radially collapsed configuration which is sufficiently compact to allow the graft to be transluminally advanced through the vasculature until it reaches the intended site of implantation. Thereafter, the graft (and the accompanying graft anchoring device) expands to a radially expanded configuration which is large enough to exert the desired outwardly-directed pressure against the blood vessel wall. In some embodiments, hooks, barbs, or other projections formed on the graft anchoring device, will insert into the wall of the blood vessel to ensure that the graft will be fly held in its desired position, without slipping or migrating after implantation. These radially expandable graft anchoring devices are generally classifiable as either a.) self-expanding or b) pressure-expandable. Graft anchoring devices of the "self-expanding" are usually formed of a resilient material (e.g., spring metal) or shape memory alloy which automatically expands from a radially collapsed configuration to a radially expanded configuration, when relieved of surrounding constraint (e.g., a surrounding tubular sheath or catheter wall). On the other hand, those of the "pressure-expandable" variety are typically formed of malleable wire or other plastically deformable material which will deform to a radially expanded configuration in response to the exertion of outwardly directed pressure thereagainst--as by inflation of a balloon or actuation of another pressure-exerting apparatus which has been positioned within the graft anchoring device.
Endovascular grafting is a clinically viable alternative to traditional surgery in patients who suffer from aneurysms of the aorta. Indeed, may patients who are diagnosed with aortic aneurysms are in relatively poor health, and may be characterized as poor surgical risks. Moreover, the traditional surgical approach to repair of aortic aneurysms requires cross-clamping of the aorta above the aneurysm, which can result in ischemic damage to organs or other untoward results. Nonetheless, if allowed to remain untreated, a substantial percentage of aortic aneurysms may ultimately dissect or rupture, with catastrophic consequences. Thus, endovascular grafting offers a potential means for repair of aortic aneurysms, without the risks and potential complications of traditional aneurysm repair surgery.
Depending on which region(s) of the aorta is/are involved, the aneurysm may extend into areas of bifurcation (i.e., the inferior end of the aorta where it bifurcates into the iliac arteries) or segments of the aorta from which smaller "branch" arteries extend. In this regard, the various types of aortic aneurysms may be classified on the basis of the region(s) of aneurysmic involvement, as follows:
A. Thoracic Aortic Aneurysms: PA0 B. Thoracoabdominal Aortic Aneurysms: PA0 C. Abdominal Aortic Aneurysms: PA0 a) a primary graft which comprises; PA0 b) a branch graft which comprises; PA0 a) transluminally advancing the primary graft into the branched anatomical conduit; PA0 b) positioning the primary graft within the anatomical conduit such that the branch opening is aligned with the branch anatomical conduit; PA0 c) utilizing the primary graft anchoring device to anchor the primary graft within the anatomical conduit; PA0 d) transluminally advancing the branch graft into the lumen of the primary graft; PA0 e) passing the distal end of the branch graft through the branch opening and into the branch anatomical conduit; and, PA0 f) advancing the branch graft into the branch anatomical conduit until the second connector on the proximal end of the branch graft engages the first connector of the primary graft, thereby connecting the branch graft to the primary graft such that body fluid (e.g., blood) may flow from the lumen of the primary graft, through the branch opening, and through the lumen of the branch graft. PA0 g) utilizing a branch graft anchoring device to anchor at least the distal end of the branch graft to the surrounding wall of the branch anatomical conduit. PA0 a. providing a modular endoluminal graft which comprises i) a primary graft which is configured to be positioned in the main portion and first furcation of the anatomical conduit, and which has an opening formed therein, and ii) a branch graft which has a proximal end and a distal end and which is configured to be positioned in the second furcation of the anatomical conduit with its proximal end connected to the opening formed in the main graft; PA0 b. forming an access opening which leads into the first furcation of the anatomical conduit; PA0 c. advancing the bifurcated primary graft through the access opening and positioning the primary graft in the main portion and first furcation of the anatomical conduit; PA0 d. advancing a curved guide catheter having an internal angle of curvature less than 90 degrees, into the main portion of the primary graft; PA0 e. advancing a guidewire having a distal end, through the curved guide catheter, such that the distal end of the guidewire passes out of the curved guide catheter, through the opening formed in the primary graft, and into the second furcation of the anatomical conduit; PA0 f. advancing a catheter having the branch graft mounted thereon, over the guidewire until the distal end of the branch graft extends into the second furcation of the anatomical conduit and the proximal end of the branch graft is connected to the opening formed in the primary graft; and, PA0 g. removing said guidewire and said catheter. PA0 a) a balloon-anchorable guidewire which comprises: PA0 b) an inflation syringe/lumen-plugging apparatus which comprises:
Aneurysms involving the ascending thoracic aorta PA1 Aneurysms involving the aortic arch and branch arteries which emanate therefrom (i.e., the subclavian arteries) PA1 Aneurysms involving the descending thoracic aorta and branch arteries which emanate therefrom (i.e., thoracac intercostal arteries) and/or the suprarenal abdominal aorta and branch arteries which emanate therefrom (i.e., renal, superior mesenteric, celiac and/or intercostal arteries). PA1 Aneurysms involving the pararenal aorta and the branch arteries which emanate therefrom (i.e., the renal arteries) PA1 Anneurysms involving the infrarenal aorta with or without iliac involvement PA1 i) a first pliable tube (e.g., a tube formed of woven polyester, expanded polytetrafluoroethylene (ePTFE), or other biocompatable material) having a lumen extending longitudinally therethrough; PA1 ii) at least one branch opening (e.g., an aperture) formed in the first pliable tube; PA1 iii) a first connector (e.g., a groove, slot, depression, or other engageable surface) associated with (e.g., formed around or positioned adjacent to) the branch opening; and, PA1 iv) a primary graft anchoring device (e.g., a radially expandable stent, frame, series of rings, and/or adhesive, suture(s), staple(s), etc. for holding the graft in place) which is operative to hold the first pliable tube in a substantially fixed position within the lumen of the anatomical conduit, such that the branch opening is in alignment with the branch anatomical conduit; and, PA1 i) a second pliable tube having a proximal end, a distal end, and a lumen extending longitudinally therethrough; PA1 ii) a second connector (e.g., a ring, rib, ridge, protrusion or other engageable surface) associated with the proximal end of the second pliable tube, said second connector being engageable with said first connector to connect the proximal end of the second pliable tube to the first pliable tube such that fluid which flows through the lumen of the primary graft may pass through said branch opening and into the lumen branch graft. In some applications, it will be desirable for the branch graft component of the above-summarized endoluminal grafting system to further include, or to be used in conjunction with, PA1 iii) a branch graft anchoring device (e.g., a radially expandable stent, frame, rings, and/or an adhesive, suture(s), staple(s), etc.) which is operative to hold at least the distal end of the branch graft in contact with the surrounding wall of the branch anatomical conduit. PA1 i) an elongate guidewire having a proximal end and a distal end; PA1 ii) a balloon formed on the guidewire at a first location; PA1 iii) a lumen which extends longitudinally through the guidewire from its proximal end to said balloon, said lumen being useable to pass inflation fluid into and out of said balloon; and, PA1 i) a syringe having a plunger and a barrel, said syringe being connectable to the proximal end of the guidewire such that when the plunger of said syringe is advanced in a first direction it will force inflation fluid through said lumen in the distal direction and into said balloon and, when said plunger is retracted in a second direction it will draw inflation fluid out of said balloon and through said lumen in the proximal direction; and, PA1 ii) a lumen-plugging member releasably mounted on the plunger of the syringe such that, when the plunger is advanced in the first direction to a predetermined point, the lumen-plugging member will become inserted into the guidewire lumen and is subsequently releasable from the plunger, said lumen-plugging member being thereby operative to prevent inflation fluid from escaping from said lumen when the syringe is removed.
Unfortunately, not all patients diagnosed with aortic aneurysm are presently considered to be candidates for endovascular grafting. This is largely due to the fact that most of the endovascular grafting systems of the prior art are not designed for use in regions of the aorta from which side branches (i.e., carotid, innominate, subclavian, intercostal, superior mesenteric, celiac or renal arteries) extend. In fact, most of the clinical experience with endoaortic grafting has been for the treatment of infrarenal aneurysms, with or without illiac involvement. Examples of endovascular grafting methods and systems useable to treat such infrarenal anneurysms include those described in the following U.S. Pat. Nos. 4,577,631 (Kreamer); 5,211,658 (Clouse); 5,219,355 (Parodi et al.); 5,316,023 (Palmaz et al.); 5,360,443 (Barone et al.); 5,425,765 (Tifenbrun et al.); 5,609,625; (Piplani et al.); 5,591,229 (Parodi et al.); 5,578,071 (Parodi); 5,571,173 (Parodi); 5,562,728 (Lazarus et al.); 5,562,726 (Chuter); 5,562,724 (Vorwerk et al.); 5,522,880 (Barone et al.); and 5,507,769 (Marin et al.).
Most if not all of the endovascular grafts which have been designed for use in treating infrarenal aneurysms require that a proximal "neck" (e.g., at least two (2) centimeters of non-aneurysmic aorta) exist inferior to the renal arteries, in order to provide a region where the superior end of the graft may be securely anchored in place, without blocking or restricting blood flow into the renal arteries. The deployment of endovascular grafts within regions of the aorta from which branch arteries extend (e.g., regions of the aorta from which the renal, superior mesenteric, celiac, intercostal, and/or subclavian arteries emanate) present additional technical challenges because, in those cases, the endovascular graft must be designed, implanted and maintained in a manner which does not impair the flow of blood into the branch arteries.
U.S. Pat. No. 5,425,765 (Tifenbrun et al.) has described an endovascular graft which has one or more openings or fenestrations formed at specific locations, to allow blood to flow from the aorta into one or more branch arteries. However, such fenestrations do not form discrete conduit(s) through which blood is channeled into each branch artery. As a result, the area surrounding the fenestrations could be prone to i) the leakage of blood into the space between the outer surface of the aortic graft and the surrounding aortic wall or ii) post-implantation migration or movement of the graft causing misalignment of the fenestration(s) and the branch artery(ies)--with resultant impairment of flow into the branch artery(ies).
Thus, in view of the above-discussed limitations and shortcomings, there remains a need in the art for the development of new endovascular grafting systems and methods which a) may be useable for endovascular grafting in regions of a blood vessel (e.g., aorta) from which branch blood vessels (e.g.,carotid, innominate, subclavian, intercostal, superior mesenteric, celiac, renal or iliac arteries) extend, and/or b) may enable more aortic aneurysm patients to be considered as candidates for endovascular repair, and/or c) may otherwise advance the state of the art of endovascular grafting to improve patient outcomes or lessen complications.